TM 1–1520–238–T–1
Change 8
3–13
3–3
APU – OPERATING INSTRUCTIONS (cont)
3–3
WARNING
To prevent accidental APU start, ensure
that the APU circuit breaker in the AFT
avionics bay or the APU HOLD and the
APU FUEL circuit breakers on the pilot
center circuit breaker panel are open when
battery or external electrical power is
attached to the helicopter and unqualified
personnel are in and around the pilot crew
station.
APU fires may go unnoticed by
crew/operators in crew stations. Post a
fire guard in continuous communication
via the intercommunication system (ICS)
with the crew/operators during APU
run–up.
NOTE
If any aircraft subsystem requires servicing after
it has been briefly checked, perform the
required servicing prior to proceeding to the
next step.
1. The following procedures specify APU operator
walk–around and external checks.
a. Verify the following fluid servicing points for proper
levels prior to APU operation and add as required
(TM 1-1520-238-23).
(1) Main transmission oil level (left and right side)
(2) APU oil level
(3) Utility hydraulic fluid level
(4) Primary hydraulic fluid level
(5) Aft fuel tank level
CAUTION
Use of excessive force to actuate hydraulic
hand pump could cause damage to aircraft
components.
b. Verify external utility hydraulic pressure gage is
indicating within the range of 2600 to 3000 psig. If
hydraulic pressure is below 2600 psig, use the hand
pump to increase pressure to 3000 psig.
